Horizontal broach



June 20, 1939. w, HART HORIZONTAL BRoAcH 6 Sheets-Sheet 1 Filed Feb. 15, 1936 INVENTOR. Hl'lZZ dm Hard.

ATTORNEYS.

' June 20, 1939. w. A. HART HORIZONTAL BROAGH Filed Feb. 15, 1936- 6 Sheets-Sheet 2 I June 20, 1939. w A H RT 2,162,814

HORIZONTAL BROACH Filed Feb. 15, 1936 6 Sheets-Sheet 3 ATTORNEYS.

June 20, 1939. 1 w A H T I 2,162,814

HORIZONTAL BROACH Filed Feb. 15, 1936 e Sheets-Sheet 4 ix INVENTOR. l1 l/ari. I BY Q firroxzz s.

June 20, 1939. w. A. HART HORIZONTAL VBROACH 6 Sheets-Sheet 5 Filed Feb. 15, 1936 mzligw 3 1 ORNEYS.

Patented June 20, 1939 UNITED STATES HORIZONTAL BROACH William A. Hart, Detroit, Mich., assignor to Colonial Broach Company, a corporation of Michigan Application February 15, 1936, Serial No. 64,062

Claims.

The present invention relates to machine tools, and in particular provides an improved fully automatic broaching machine.

Objects of the present invention are to pro- {5' vid-e an improved broaching machine of the fully automatic type, in the operation of which work may be positioned in breaching position, a broach then advanced through the work piece, the work piece then automatically moved away from broaching position, and the broach then returned to a starting position in readiness for a subsequent operation; to provide such a machine embodying, as independent but inter-controlled elements, a broach draw-head, a broach return head, a discharge mechanism, and means for operating such elements; to provide such a machine in which the broach draw-head advances the broach through the work and, subsequent to the action of the work discharge mechanism, returns the broach to a starting position in which the broach return head is eifective to move the broach to a loading position, in which the broach is free of the work piece supporting mechanism and permits insertion of a new work piece; to provide such a machine embodying fluid pressure operated mechanism for operating the several broaching heads and the discharge mechanism; to provide such a machine in which the fluid pressure operated mechanism includes a cylinder and associated piston individual to each of the broaching heads, and a cylinder and associated piston individual to the discharge mechanism, which several fluid pressure mechanisms are inter-controlled to effect the above mentioned sequence of operation.

Further objects of the present invention are to provide an improved breaching machine as above generally stated, in which the discharge mechanism for the completed work pieces is rendered effective at the conclusion of a Working stroke of the broach draw-head, to positively discharge a completed work piece from the machine prior to the return movement of the broach draw-head; and in which the return movement of the broach draw-head is dependent upon the prior discharge from the machine of the work piece by the discharge mechanism;

Further objects of the present invention are .to provide an improved breaching machine as above generally stated, embodying means to accurately and readily position, and to positively lock, the work piece in broaching position; embodying means responsive to the completion of a broach Working stroke for unlocking the looking mechanism; to provide such a machine embodying locking mechanism for the work piece, jointly controlled by the starting means for the machine and by the broach working head; and to provide such an arrangement in which manual control means are provided to initiate a com- 5 plete broaching cycle, which manual control means automatically renders the locking mechanism effective; and embodying means responsive to the completion of a broaching operation for unlocking the locking mechanism.

Further objects of the present invention are to provide an improved automatic broaching machine of the above generally stated character, embodying a novel disposition of the several operating and control parts, resulting in a more compact and generally more efl'lcient machine; and to provide an automatic breaching machine embodying generally improved details of construction.

With the above and other objects in View which appear in the following description and in the appended claims, a preferred but illustrative embodiment of the present invention is shown in the accompanying drawings, throughout the several views of which corresponding reference characters are used to designate corresponding parts. and in which:

Figure 1 is a perspective View, in side elevation, of the improved machine;

Fig. 2 is a view, in vertical section, taken along the line 22 of Fig. 1;

Figs. 3 and 3A, collectively, .are a View in vertical section, taken along the line 3, 3A-3, 3A of Fig. 2, these figures being conveniently considered together by placing Fig. 3A immediately to the right of Fig. 3;

Fig. 4 is a sectional view in top plan, taken along the'line 4-4 of Fig. 1;

Fig. 5 is. a fragmentary sectional View, taken along the line 5-5 of Fig. 4; 40

Fig. 6 is a fragmentary view in vertical section, taken along the line 6-6 of Fig. 5;

Fig. 7 is a fragmentary view in vertical section, taken along the line 'l'! of Fig. 5;

Fig. 8 is a diagrammatic View of suitable control mechanism for effecting the preferred operating sequence of the machine; and

Fig. 9 is a view of an alternative broach head construction which may be used in the practice of the invention.

Referring first to the general view, Fig. 1, the preferred construction is of the horizontally disposed type, and comprises generally a supporting frame structure i0 provided with upstanding centrally disposed but spaced abutments I2 and it between which the work piece l6, illustrated as a conventional cylinder block for an internal combustion engine, is received and is slidable inwardly and outwardly upon a work supporting table it. The shank 20 of the draw-head, hereinafter described in more detail, is rigidly but removably secured by nuts 22 to a boss at positioned above but axially parallel to a working cylinder 26 and connected thereto by ribs 28.

Cylinder 26 is slidable within ways 36 formed within the machine frame. The broach return head, not shown in Fig. 1, described in more detail hereinafter, is also rigidly but removably connected to a crosshead 32, slidable on longitudinally extending guide rods 34 and 36 which extend between the abutment l4 and a similar abutment 38 positioned at the left-hand end of the machine as viewed in Fig. l. Crosshead 32 is operated by a piston in a cylinder ll) suitably housed within a frame portion 42 which is positioned above and extends between the previously mentioned abutments I2 and M.

'It will be noted that the operating mechanism for the breach heads is thus disposed in axially displaced but longitudinally overlapped relation, the cylinder for the broach return head being disposed substantially directly above the working position of the machine and the cylinder for the broach draw-head being disposed substantially directly beneath the working position. With this arrangement, the overall length of the machine is required to exceed the overall spacing between the abutments l2 and it which define the working position only sufficiently to accommodate the desired length of stroke of the broach heads.

The discharge mechanism hereinafter described in more detail, does not appear in Fig. 1, but as shown clearly in Fig. 2, comprises generally a cylinder housing M positioned at the rear of the machine substantially centrally thereof in position so that the plunger 2H5 thereof may force the work piece l6 forwardly of the machine to a position in which it is free of the path of travel of the broach.

The necessary control mechanism for operating the broach is conveniently disposed upon the front of the machine for ready operation by the operator thereof and, as illustrated, causes the manual starting handle 68, which, as hereinafter described, serves to initiate a complete broaching cycle and also serves to actuate mechanism to positively lock the work piece it in the broaching position shown in Fig. 1; an emergency stop handle 56; and suitable indicating mechanism illustrated as a meter 52, which may serve to indicate the load upon the broach working head.

Considering the above mentioned elements in more detail and referring particularly to Figs. 3, 3A and 4, the broach draw-head, designated as a whole as 62, is of the automatic locking and unlocking type, embodying the previously mentioned tubular shank 20, the bore of which freely slidably receives the end of broach 62, an outer sleeve 64, and a plurality of radially disposed locking pins 66, which are received in radially extending passages'formed in shank 26 and in corresponding angularly spaced recesses 63 formed in sleeve 64.

Sleeve 62 is slidable axially of shank 26 and is continuously urged to the left, as viewed in Fig. 3A, by a compression spring 14 seated between an inwardly extending lug 15 formed on sleeve 65 and an axially aligned shoulder formed in shank 26. The spring 14 thus limits rightward movement of sleeve 6% (as viewed in Fig. 3A) and opposite movement thereof is limited by a removable stop pin 'HJ secured in sleeve 64, the end of which is received in a slot 12 formed in shank 20.

The locking pins 66 are freely movable within the associated radial slots formed in shank 26, the inward movement thereof being limited either by engagement of the chamfered inner ends thereof with broach 62 or by engagement between stop pins 16 secured thereto which ride in slots formed in shank 20. The outward movement of locking pins 66 is limited by engagement of the outer ends thereof with the surface of sleeve 64.

The parts of broach head 66 are shown in the broach released position, in which sleeve 64 is forced to the right relative to shank 26, as viewed in Fig. 3A, against the force of compression spring 14, having been moved to this position at the conclusion of a return movement of cylinder 26 by the engagement of sleeve 64 with one or more adjustable stops 30 which comprise studs threaded into the wall of the previously mentioned centrally positioned abutment l2. With the parts in this position broach 62 may be freely removed from broach head 60, the removal thereof camming the upper locking pin 66 upwardly out of the locking notch 82 formed in the shank on broach 52 into the associated recess 68, and the lower locking pin having fallen by gravity to a corresponding retracted position. Upon removal of broach 62, the upper locking pin 66 may be expected to fall inwardly of the locking head 60, under the influence of gravity, the inward movement thereof being limited as previously described by the stop pin 16 associated therewith. The lower pin 66 remains supported by the recess 68 associated therewith formed in the sleeve 64. With the parts in the illustrated positions, broach 62 may also be freely inserted into head 66, the inserting movement having no effect upon the lower locking pin 66, but camming the upper locking pin 86 upwardly sufficiently to permit the broach to enter and finally permitting locking pin 66 to again fall into the locking notch 82 of the broach. If locking head 60 is now released from the stop 8|], as by movement to the right, as viewed in Fig. 3A, of boss 24, sleeve 62 moves to the left relative to shank 20 under the influence of compression spring M, moving the recesses 68 out of registry with the locking pin 65 and moving the sleeve portion 84 into registry with the end of the locking pin, sleeve 64 being provided with the angled cam shoulders 86 between the recesses 6B and the sleeve portion 84, which cam the locking pins 66 inwardly of the head and positively retain them in locking position.

The cylinder 26, which actuates the broach draw-head 60, is slidably supported upon ways 30 formed in the machine frame, as previously stated, and reciprocates along said ways from the starting position thereof shown in the various figures to a limit position to the right of the position shown. Cylinder 26 and its cooperating piston 9B are preferably constructed in accordance with the disclosures of the co-pending application of the present applicant, Serial No. 42,619, filed September 28, 1935, and assigned to the same assignee as the present application, As there described in more detail, cylinder 26 comprises an outer casing and an inner cylinder 92 within which the piston 90 is positioned. Piston 96 is secured at the end of a piston rod formed of two telescoped tubes 94 and 96, which extend through an opening formed in a closure plate 98 I 36 respectively, the opposite ends of which are secured at the left-hand end of cylinder 26, as viewed in Fig. 3, and are secured in a head I08 which in turn is suitably secured to and supported by the machine frame I 0. A suitable packing gland I82 is interposed between the closure plate 98 and the outer tube 96.

The inner tube 94 is threaded into an axial bore I94 formed in piston 90 and thus communicates with the interior of casing 92 on the right-hand side of piston 90. The outer tube 96 is provided with one or more radial ports I06 through which communication is had between the interior of tube 96 and the interior of casing 92 on the lefthand side of piston 99. The head I98 is provided with ports I98 and I I!) which communicate respectively with tubes 94 and 96 and which are selectively connected through suitable lines H2 and II 4 to a suitable source of fluid pressure, through the hereinafter described control system. It will be evident by connecting line H2 to the source of pressure and line II4 to exhaust, fluid under pressure is admitted to casing 92 on the right-hand side of piston 99 and is exhausted through tube 96 from the casing portion on the left-hand side of piston 98, thus causing cylinder 26 to move bodily to the right, as viewed in the several figures. By reversing the connections, fluid is exhausted from the chamber space to the right of piston 96 and is admitted to the chamber space to the left of piston 98, thus causing cylinder 26 to move bodily to the left, as viewed in the several figures.

In the construction shown in detail in Figs. 3 and 3A a locking head I28 corresponding in all respects to the locking head 69 described above, is provided in connection with the return broaching head i22, which is disposed for actuation by the previously identified cylinder 46 and associated elements. It is considered unnecessary therefore to further describe the locking head I28 except to note that in the drawings, stop pins I25 are disposed in the path of the head to effect the releasing movement thereof, which correspond to the releasing studs 86. It will be understood that head I28 is shown in the broach releasing position, in which broach 62 may freely be removed therefrom or inserted therein and that head I28 assumes a locking position upon retraction thereof out of range of the stop pins I25, in the manner described with reference to head 66.

As an alternative to the locking head I26, a releasable head of the type shown in Fig, 9 may be used, in which figure the head comprises a sleevelike member I58 provided with a plurality or" radially extending passages I 52, each of which accommodates a spring pressed detent I54 which may be retracted by applying a predetermined separating force between the broach 62 and the head, andwhich are resiliently urged to locking position by the associated compression springs I59. In certain instances, a broach head of this character is satisfactory for use in connection with the return mechanism, since the principal purpose thereof is to move the broach between starting and loading positions, during which time no broaching action is effected by the broach.

The shank E22 of return broach head 529 is slidably received in a boss H4 which forms part of the cross head 32 and is secured in place axially thereof by a nut iZS, which may be turned down to force the end of boss I24 against a shoulder 132 formed in shank iZZ. Crcsshead 92, as best shown in Fig. 4, comprises the two bosses E32 and which are supported by and disposed to slide along the previously mentioned guide rods 34 and supported in openings I48 and I42 formed in the abutment I4 respectively and in corresponding openings formed in the end abutment 38. The crosshead 32 is connected by ribs I68 to a boss I62 which is positioned above and intermediate the two bosses I32 and I34, and consequently as best shown in Fig. 4, is substantially directly over the boss I24 which carries the broach return head 29.

The piston rod I64 associated with the broach return cylinder 46, is axially fixed in boss I62, between the lock nuts I66 and I68, and extends through a suitable packing gland I'Iil associated with the closure plate N2 of cylinder 49, terminating in a conventionalpiston I'I4 which is slidable within the casing I'IG of cylinder 40. Cylinder 48 as a whole, as previously described, is supported above the level of the loading position of the machine within the frame portion 42. The closure plate I12 associated with cylinder 49 is provided with a pocket H8 which communicates with a port 556 to which a suitable fluid supply line may be connected, to admit and exhaust fluid from the chamber space on the left-hand side of piston I1 4. The corresponding closure plate I82 for the right-hand end of cylinder 4-6 is provided with a corresponding pocket I84 which communicates through a port I86 with a similar supply line I88 through which fluid may be admitted and exhausted from the chamber space on the right-hand side of piston H4. The control mechanism for selectively connecting the ports I and 526 to a source of fiuid pressure and to an exhaust line is described hereinafter.

Considering the work supporting and discharging mechanism in more detail, the previously described table I8 includes a bracket I99 which extends outwardly from the machine at the front thereof and forms a support upon which the work piece 56 may be rested prior to being moved to the working position, and upon which the work is discharged by the discharge mechanism at the conclusion of a broaching operation. Immediately to the left of the bracket portion I98, as viewed in Fig. 2, the work table I8 includes a supporting table structure, the particular formation of which, it will be understood, depends upon the form of the work piece to be broached, and, in the illustrated embodiment, comprises the two spaced table sections 92 and I94. Guide strips I96 and I98 are associated with the table portions I 92 and I94 respectively and constitute the direct supports upon which the work piece I6 rests. Corresponding guides 299 and 262 are supported within the machine frame and are positioned directly above the guides I96 and I98, respectively, the vertical spacing between the related pairs of guides being substantially equal to the vertical dimension of the work piece i 6, which is accordingly rather snugly received between the four guides. During a breaching operation, the right-hand end Ifia of the work piece IE bears against a plate 284, positioned in bearing relation to the previously mentioned abutment l2. Removable spacing. blocks, such as 266, are preferably interposed between the left-hand end I 6b of the work piece and the abutment I4.

The discharge mechanism 44 comprises generally, as best seen in Fig. 4, a cylinder 2 l6 secured within a bracket 2I2 mounted upon the machine frame at the rear side thereof and provided with a piston rod 2 I4 with which a suitable piston (not shown) is associated, effective to move piston rod 2 I 4 from the illustrated retracted position through a forward or working stroke to the right, as viewed in Fig. 2, and also to move it through a return stroke to the left, as viewed in Fig. 2.

The end of piston rod 2M bears against ahead or bar 2l6 guided within a track or way 2 i 8 which is supported by the machine frame and which, as best seen in Figs. 3 and 3A, is positioned intermediate and somewhat below the work table portions I92 and 194. The block 2i bears directly against the rear side of work piece it and when in its retracted position, permits insertion of work piece 5 to the working position with reference to the breach I52 but forms a positive limit to such movement, being adjusted to block movement of work piece it when the latter reaches a position of substantial alignment with broach 62. As will be evident, however, an outward movement of block 2H5, as effected by the discharge mechanism id, positively moves the work piece away from the working position out upon the external supporting bracket 55%. Any desired'mechanism may be utilized to convey the completed Work piece away from bracket E95 and to convey new work pieces thereto, as well as to feed the new work pieces from the loading position to the working position, this operation being eifected manually in accordance with the illustrated construction.

In further accordance with the preferred embodiment of the present invention, means are provided to positively lock the work piece It in the working position during the broaching action and, as hereinafter described in more detail, this mechanism is arranged for control by and in accordance with the operation of the machine starting handle and of breach head 55]. Referring particularly to Figs. 4, 5, 6 and '7, locking pins 228 and 222 are slidably supported within sleeves 224% and 226, respectively, which are fitted into passages formed in the machine frame Iii and, as shown in Fig. 4, are positioned to engage the base of work piece 8 at points adjacent the respective ends thereof and at or near the transverse center thereof. It will be understood that the work piece [6 is provided with recesses into which the tapered ends 223 and 23B of the pins are received, which recesses are accurately located relative to the work piece so that when the ins are engaged therein the work piece It is positively maintained in accurate alignment with the path of travel of the broach.

The raising and lowering of locking pins 225 and 222 between a lowered retracted position, and the raised locking position illustrated in Figs. 5 and '7, is effected by a cam bar 232 which is slidable within a passage 23G formed in the machine frame and is provided with two pairs of cam shoulders 235, 238, 240 and 222, respectively. Bar 232 passes through transverse openings formed in the pins 223 and 222, respectively, and in the associated supporting sleeves, the openings in the pins being provided with angled faces 244 and 245 and 248 and 252, respectively, to cooperate with the corresponding cam surfaces of the bar.

It will be understood that with the parts in the positions illustrated in Fig. 5, pins 220 and 222 are positively projected to the upper or looking position and are supported therein by the bar 232, the straight upper portions of which are in supporting relation to corresponding portions of the passages through the pins. Movement of bar 232 to the right, as viewed in Fig. 5, however, brings the relieved portions 252 and 254 thereof into registry with pins 220 and 222, respectively. The bar movement positively retracts the pins,

because of the camming relationship between the angled surfaces 238 and 245 and the corresponding surfaces 242 and 258. Similarly, movement of bar 232 from a position to the right of the illustrated position to the illustrated position results in positively projecting pins 220 and 222 to the illustrated position, the projecting movement being effected by the camming relationship between the angled surfaces 244 and 236 and the correspondingly angled surfaces 248 and 240.

Referring particularly to Figs. 5 and 6, the lefthand end of bar 232, as viewed in Fig. 5, is provided with rack teeth 269 with which a pinion 262 meshes. Pinion 262 is carried by a trunnion 254 journaled in bosses 26% and 25B either forming part of or suitably secured to the main machine frame H3.

The operating handle 48 (Figs. 1 and 6) which, as hereinafter described, preferably also controls the fluid pressure control connections to initiate the starting of a complete breaching cycle, is suitably secured upon a shaft 210, journaled within the machine frame, and provided with a pinion 212. A rack bar 214, provided with rack sections 276 and 218, extends between the pinions 2'12 and 262. As appears clearly evident in Figs. 1, 5, 6 and 8, rotation of handle 48 in a clockwise direction correspondingly rotates pinion 272 and, through rack bar 27%, also correspondingly rotates pinion 262 to actuate locking bar 232 to the left from the unlocked to the locked position described above. A link 238 is connected to bar 232 and, as shown in Fig. 1, extends to a suitable control head 282 adjacent the limit position of cylinder 26. As shown in Fig. 3, the approach of cylinder 26 to its right-hand limit position brings a earn 322 into engagement with and rotates a bell crank 322. Bell crank 322 is connected to link 2% through push rods 323 and 32 i and bell cranks 326 and 328. Push rod 324 has a lost motion connection with bell crank 328 and the above lef ward movement of link 2112 lifts a collar 33: on push rod 32 into engagement with bell crank 328. Thus, when bell crank 328 is rotated in response tothe arrival of mechanism 26 at the end of its stroke, bar 280 and handle it are restored to their original positions.

The present invention embraces within its scope the provision of automatic control mechanismv responsive to operation of the previously mentioned control handle 28 for controlling the locking and unlocking mechanism associated with the work piece 16 and described with reference to Figs. 5 and 6, and for initiating the sequential and interlocked operation of the various actuating mechanisms 26, 4!! and ,4, for the broach' drawhead 59, the broach return head i213, and the discharge mechanism The mechanical elements involved in the automatic control of the sequential movements of the latter elements are housed within the lower part of the enclosing machine frame, and thus do not appear in the figures thus far described. These elements are shown in the remaining Figure No. 8. Referring to Fig. 8, the working, return, and discharge mechanisms 2 5, 45, and Mi, may be provided with valves 32%, 3-62 and 32 5, respectively, which are individual thereto and each of which is preferably of the type which may be successively actuated from one operating position to another by unidirectional movement of an operating shaft associated therewith. The valve 335 associated with the cylinder 25 is adapted to provide an off position in which flow through the valve is prevented, and consequently cylinder 26 is maintained at rest; an on 7 forward position, in which connections are completed to effect movement of cylinder 26 to the right, as viewed in the figures; a second off position in which cylinder 26 is maintained at rest; and an on return position in which connections are completed through the valveto cause cylinder 23 to move to the left through a return stroke, as viewed in the figures. The valve 362, associated with the return cylinder 30, is similarly arranged.

The valve 334 associated with the discharge cylinder 3 is provided with only three individual operating positions including an on forward position in which the valve completes suitable connections to effect a discharge or forward movement of the discharge mechanism; a reverse position in which the valve completes connections to effect a return movement of the discharge mechanism; and an off position in which flow through the valve is prevented and the discharge mechanism is maintained in its withdrawn or retracted normal position. I

Valve 3% is illustrated as provided with an operating shaft 336, which is disposed for notching rotation in a clockwise direction by the cranks 336a, 333b, 3360, and 33302, each of which is connected thereto by a lost motion or ratchet connection, so that rotation of an individual crank in a clockwise direction is effective to correspondingly rotate arm 336 one notch or the distance between successive operating positions in the same direction, but so that arm 33% may be rotated independently of such particular crank. Valve3fl2 is provided with a similarly arranged operating shaft 338 having associated therewith in the manner just described four operating cranks 333a, 338b, 3330 and 338d. Valve 304 is provided with a corresponding operating arm sac, provided with similarly associated cranks 3l3a, 3|[lb and 3l0c. As clearly appears in Fig. 8, crank 338a is disposed for manual movement by the previously identified handle 43 to thereby initiate the operating cycle. For this purpose the shaft 27!! associated with crank 38 is connected to the crank 398a through a pushv rod 332. Sim-.

ilarly, cranks 336a. and. 338bare disposed for actuation by the return mechanism 40 at the conclusion of a forward stroke thereof, substantially at the same time that piston l 14 associated therewith reaches the starting position illustrated in the previously described figures. For this purpose the cross-head 32 associated with cylinder 40 carries a cam 334 which engages and rocks a bell crank 335 at the conclusion of the just mentioned forward stroke. Bell crank 333 is connected to crank 3218b through push rod 338 and is also connected to crank 336a through the additional push rod 330. Cranks 33th and 353a are disposed for actuation by the working mechanism 26 when said mechanism reaches the end of its working stroke, that is, the extreme righthand position thereof as viewed in the several figures. This action is effected through the operation of the previously described bell crank 322, which operates a push rod 332 through the push rod 323. Push rod 342 in turn is connected to the cranks 3 Isa and 3361). Crank 35% is disposed.

for actuation by the discharge mechanism 44 when said mechanism reaches its forward or extended'position after having moved a completed" workpiece out of the machine. For this purpose the head 2&6 associated with cylinder 44 is provided with a cam 333 which engages and looks a control lever 343. Lever 335 is connected to crank 3lllb through a push rod 344. Cranks 3630 and mechanism 44 upon the arrival thereof at its normal or retracted position. This action is effected through the engagement of cam 343 with a lever 348. The lever 348 operates cranks 3100 and 3360 through push rods 353 and 352. Cranks 306a! and 3080 are disposed for actuation by the working mechanism 26 upon the arrival thereof at substantially the position shown in the previously described figures, that is, at the starting position. This action is effected through push rods 354 and 356, which are actuated by a bell crank 358. Bell crank 358 is engaged by the cam 323 when cylinder 26 reaches its starting position. The rema ning crank 308d is disposed for actuation by'the return mechanism 33 upon the return thereof to its extreme left-hand position, that is, the loading position of the machine. This action is accomplished through a push rod 360 which is operated by the cam 334 through a bell crank 35f. It will be noted that each of the cam operated bell cranks is provided with a return spring such as 362 (bell crank 358) to restore the respective bell cranks and push rods to the original positions thereof as soon as the cams pass out of operating engagement therewith.

Valves 330, 332 and 334 each communicate through lines 3l2, 3M and 3l6, respectively, with a suitable manifold 3E8 which may lead to a suitable sump. The valves also are connected, through suitable lines 323, 322 and 323, with a suitable distributing manifold 325 which leads to a suitable source of fluid pressure which may comprise the motor driven pump 328, shown in Fig. 1, and positioned within the machine frame. Preferably, and as illustrated, a suitable emergency stop valve 333 is positioned in the manifold 326 and through suitable connections (not shown) is arranged for control by the previously mentioned emergency stop lever 50 positioned upon the front of the machine, as shown in Fig. 1.

Operation as a whole Considering now the operation of the machine as a whole, the parts of the machine are, for convenience, shown in Figs. through 8 in the start ing, positions thereof. In practice, with the illustrated control arrangement (Fig. 8), the parts normally occupy positions of rest corresponding to a loading position in which the discharge and working mechanisms 43 and 26 occupy the positions shown and the return mechanism 40 occupies an extreme left-hand position in which head l2!) supports broach E2 in a retracted or loading position. In the loading position broach 62 does not interfere with the removal and insertion of work piece It.

Assuming a work piece it has been moved into the position shown therefor in dotted lines in the respective figures, in which position, as previously described, it is rather accurately fitted between the upper guides 236 and 282, lower guides E96 and I93, face'plate'ZM, spacing bar 206 and head 2l6, the manual starting handle 48 may be actuated to initiate an automatic operating sequence, and to project the locking pins 220 and 222 into the recesses provided therefor in the work piece IS. The locking action is effected, as previously described with reference to Figs. 5 and 6, through bar 232 which responds to rotation of handle 48 and project pins 220 and 222 upwardly. This projecting action corrects any misalignment of the work piece which may exist, due to the manual insertion of the work piece,

and brings the work piece into accurate axial alignment with broach 62. This locking movement also pulls link 289 (Figs. 1, 6 and 8) to the left, presetting it for actuation by cylinder 26 through push rod 324. Handle d8 remains in the operated position for the time being.

Rotation of handle 48 also rotates crank 303a associated with valve 302 through one step in a clockwise direction, moving valve 362 to the on forward position in which it is eiTective to com plete connections to return mechanism $9 to cause it to move to the right carrying broach 62 therewith. This movement advances the forward end of broach 62 through work piece It and ultimately moves the leading end of breach 62 into the broach draw-head 663 which, in the starting and loading positions of the machine, is in a position 'to freely receive broach 62, as previously de scribed.

As the return mechanism 46, carrying broach 62 with it, approaches the right hand end of its stroke, the return broach head E25 engages the stop pins !25 (Fig. 3), resulting in the release therefrom of broach 52. At or about the same time, through push rod 338, the movement of return mechanism 40 actuates crank 32%, associated with valve 362, moving valve 302 to an off position, and thus interrupting the flow of fluid therethrough and bringing return mechanism 40 to rest at the starting position.

Through push rods 338 and 349, the arrival of return mechanism t!) at the right hand end of its stroke also actuates crank 365a, associated with valve 303, and throws this valve to an on forward position, completing fluid connections to cause a forward or working movement of the broaching cylinder 26. At the beginning of this Working movement, and as the head 66 thereof moves away from the stop pins 88, the locking pins 65 are cammed into positive locking relation to broach 62, and firmly secure it within head 66). Accordingly, the working movement of cylinder 26 positively draws broach 62 through the work piece l6.

As cylinder 26 approaches its right-hand limit of travel, it actuates link 28!! (Figs. 1 and .6), through push rod 324 and bell crank 328, and also operates cranks 3M1) and MM. Actuation of link 280 correspondingly moves lock bar 232 and pins 220 and 222 to retracted positions, in which the latter do not interfere with the discharge of work piece 16 from the machine. This movement also returns handle 48 and crank 388a to their initial positions.

mechanism 26 to rest. Crank 3Ifia throws valve 304- to the on forward position, resulting in actuating the discharge mechanism it to positively move the work piece it out of the machine upon the platform use. It will be understood that at the time cylinder 26 is brought to rest, the trailing end of breach 62 is beyond and free of the work piece 16 and thus does not interfere with the discharge movement thereof.

When discharge mechanism it approaches the limit of its stroke, by which time the work piece it is entirely discharged from the machine, the movement thereof actuates crank Slflb, through push rod 264, throwing valve 304 to a reverse position and resulting in a return movement thereof. Upon completing the return movement, discharge mechanism 44 actuates crank Blflc (through push rod 355) to throw valve 3% to the oif position, thereby bringing the discharge mechanism to rest; and also actuatcs cran 30 t0 Crank 3061) throws, valve 3% to the off position, bringing working throw valve 30!] to its on return position, in which it is efiective to complete connections to cause a return movement of the working mechanism 26.

As return mechanism 26 approaches the starting position, the sleeve 65 forming part of the broach head 6b associated therewith engages the stop pins and is thereby moved relatively to the shank 20, permitting the locking pins 66 to be moved radially outwardly, to thereby permit removal from broach head 66 of broach 62. or about the same time, through push rods 354- and 356, return mechanism 26 actuates crank 305d to bring valve 300 to the initial off position, bringing return mechanism 25 to rest at the starting position. Return mechanism 26 also actuates crank 3080, to throw valve 302 to the on return position, resulting in a movement to the left of return mechanism 45. The approach of broaching cylinder 26 to the starting position moves the left-hand end of broach 62 into the return locking head I20, so that as looking head I20 recedes from the'stop pins PM, the locking pins associated therewith are positively cammed into locking relation to broach 62, resulting in broach 52 being carried along with return mechanism 40.

As return mechanism 4!] approaches its'initial left-hand limit or loading position, it actuates crank 328d, through push rod 369, throwing valve 392 to its initial or ofi position, bringing the return mechanism to rest at the loading position. At the conclusion of the above described cycle, accordingly, the control mechanism is in its initial condition, all of the valve mechanisms being in their initial off position and the various operating parts being at rest. The machine is thus in readiness for another and duplicate cycle.

Although specific embodiments of the present invention have been described, it will be evident that various modificationsin the form, number and arrangement of parts may be made within the, spirit and scope thereof. It will also be evident that various elements of the present invention may be utilized independently of other elements thereof and may be used for purposes other than the specific purposes described. The described embodiments, accordingly, are to be regarded in an illustrative, and not in a limiting,

sense.

What I claim is:

1. A broaching machine comprising, in combination, a work table for supporting work in broaching position relative to a broach; discharge mechanism movable between retracted and projected positions and effective upon being projected to move said work along said table out of the path of said broach and eifective when in said retracted position to form a stop to preliminarily position said work relative to said breach; and locking means for accurately positioning and locking said work in said broaching position.

2. A broaching machine comprising, in combination, a work table for supporting work in broaching position relative to a broach; starting means for'said machine; a draw head for drawing a broach through said work from a starting position to a limit position and for returning said broach to said starting position; discharge mechanism for moving said work along said table out of said broaching position; means for locking said work in broaching position; means actuated by said starting means for actuating said locking means to lock said work; means actuated by said broach head as it approaches said limit ing and a return stroke, said head being effective during said working stroke to draw. said broach from a starting position through said work and effective during said return stroke to return said broach to said starting position, discharge mechanism effective to move said work out of the path of travel of said broach, means actuated by said v draw-head upon completion of the working stroke thereof for causing said discharge mechanism to move said Work out of the path of travel of said broach, and means actuated by said discharge mechanism after it has completed said movement of said work for causing said draw-head to move through said return stroke.

4. ,In a breaching machine, the combination of a work table for supporting work in broaching position relative to broach; means for moving said broach through an operating stroke relative to said work; a pair of projectable and retractable locking pins adapted upon being projected to enter cooperating recesses formed in said work to lock the same in said broaching position;

means including a link extending between said pins and having cam shoulders formed thereon for positively moving said pins in retracting and projecting directions; a start control for said broach moving means operable to move said link in a pin projecting direction; and means actuated by said broach moving means for moving said link in a pin retracting direction.

5. A broaching machine comprising, in combination, a work supporting table, a broach drawhead operable to draw a broach through a working and a return stroke, said head being efiective during said working stroke to draw said broach from a starting position through said Work and effective during said return stroke to return said broach to said starting position, dis- .charge mechanism eiiective to move said work out ;of the path of travel of said broach, a broach return head operable to deliver said broach to said broach draw-head at the beginning of a said Working stroke and to receive said broach from said broach draw-head at the conclusion of said return stroke, said broach return headbeing arranged to withdraw said broach to a retractableposition so as to permit said Work to be delivered to and discharged from said worksupporting table, means actuated by said broach return head when it delivers said broach to said broach drawhead for causing said broach draw-head to move through said working stroke, means actuated by said broach draw-head upon completion of said working stroke for causing said discharge mechanism to move said work out of the path of travel of said broach, means actuated by said discharge mechanism after it has completed said movement of said work for causing said broach draw-head to move through said return stroke, and means actuated by said broach draw-head at the conclusion of said return stroke for causing said broach return head to move said broach to said retracted position. 7

WILLIAM A. HART. 

